One method of realizing wireless power transfer is through a process known as Inductive Power Transfer (IPT) in which input power, in the form of electrical energy from a constant high frequency alternating current, is transformed into time varying magnetic fields according to Ampere's Law. On the receiving end, the magnetic field is transformed into an induced voltage according to Faraday's Law, thus creating output power for the load. The basic IPT process is illustrated in FIG. 1. Wireless power transfer may enable electric vehicles, or other electrical devices, to be continuously charged while stationary or charged in-motion with no physical connection between the vehicle/device and the roadway/power source.
Recently, some proponents assert that there are enough significant technical advances in IPT that the whole roadway system in the US could be retrofitted by IPT infrastructure to power EV's as they drive on the road. In such a system, the EV performance could be greatly improved by 1) reducing the battery cost, 2) reducing on-board battery weight and size, 3) potentially a cost effective infrastructure system. A. Brooker et al., “Technology improvement pathways to cost effective vehicle electrification,” in SAE2010 World Congress, Detroit, Mich., 2010.
IPT systems can be broadly separated into three main component groups, including the power supply, magnetic coupler, and the pickup receiver. However, prior to broad-based implementation of such systems, IPT systems and associated components must be further improved.